Solvent process



y 1934- R; E. HAYLETT SOLVENT PROCESS Filed March 19, 1952 INVENTOR. Roberz EJVqy/eff BY %Z,;,, Z a;

ATTORNEY.

Patented July 31, 1934 PATENT OFFICE SOLVENT PROCESS Robert E. Haylett, Long Beach, Calif., assignor to Union Oil Company of California, Los Angeles, Calif., a corporation of California Application March 19, 1932, Serial'No. 599,943

ll? Claims. (Cl. 196-13) This invention relates to a process for the production of lubricating oil. More specifically, the invention relates to a process for the production of lubricating oil from oils containing asphalt and wax.

I In the patent application of Ulric B. Bray, Serial No. 466,189, filed July '7, 1930, a process is set forth for the production of lubricating oil from residual oil containing asphalt and wax which consists in commingling the asphaltic oil containing wax under pressure in liquid propane, separating the undissolved asphalt from the propane solution of wax and oil, chilling the propane solution of waxy oil to a temperature sufiiciently low to precipitate the wax by vaporizing a portion of the liquid propane under reduced pressure, separating the wax from the propane solution of oil, treating the propane solution of oil with acid and alkali, and then separating the acid treated lubricating oil substantially free of wax and asphalt from its propane content by distillation.

By the term liquid propane is meant a fraction which is obtained in the rectification of natural gasoline containing amajor amount of propane. A typical analysis of such a fraction is 6.72% ethane, 72.20% propane, 19.91% isobutane and 1.17% normal butane.

While the use of liquid propane has been found to be highly satisfactory for the separation of the asphalt from the residual oil, yet certain heavy undesirable hydrocarbons remain in the oil after the asphalt precipitation which are responsible for the final product having a relatively high Conradson carbon residue (see American Society of Testing Materials Method D-189-2'7T). A high Conradson value of a lubricating oil in a certain measure indicatesthe carbon forming propensities of an oil, therefore, in refining lubricating oil fractions it is desirable to employ means which will reduce this value to a minimum. It has been discovered that the Conradson carbon value of lubricating oil produced from,

residual oil can be materially lowered by the use of a solvent composed of propane and a substantial quantity of ethane. By commingling a residual oil in a mixture of liquid ethane and propane a larger proportion of asphaltic bodies and heavy hydrocarbons responsible for high Conradson carbon residues are precipitated out from the ethane-propane.solution of oil than is the case where one employs a solvent for asphalt precipitation composed essentially of liquid propane.

The ordinary propane solvent containing 6.72% ethane, 72.20% propane, 19.91% isobutane. and 1.17% normal butane does not contain sufficient quantity of liquid ethane to materially lower the Conradson carbon value of the final product obtained by my process and to lower its viscosity-temperature susceptibility to the value desired. I have found it desirable to employ a solvent containing materially greater amounts of ethane and preferably at least 20% ethane and the balance substantially propane. By increasing the ethane content of the solvent used in my process the viscosity-temperature susceptibility and the Conradson carbon value of the final lubricating oil obtained are lowered. Thus it is desirable to use a solvent having an m ethane content as high as is practically possible without economically impairing the value of the process.

In general, lubricating oils are preferred which exhibit a low temperature viscosity susceptibility, 5 i. e., exhibit a minimum change in viscosity with a given change in temperature. Lubricating oil produced from asphaltic residues by separating the oil from the asphaltic bodies present by the use of a liquid ethane-propane mixture has a low viscosity temperature susceptibility.

The chief diificulty in employing a mixed solvent of ethane and propane having a high proportion of liquid ethane for the production of lubricating oil from asphaltic residues lies in the expensive high pressure equipment necessary for carrying out the process and in the large power consumption necessary for the liquefaction of ethane and propane after they have been separated from the oil. These two factors add materially to the cost of the final product, therefore, any modification of the process which will permit the use of an ethane-propane solvent and which is not subject to the two foregoing objections is hightly desirable.

As has been pointed out, the use of a mixed liquid solvent composed of ethane and propane is highly desirable for the separation of oil from asphaltic residues as such a solvent reduces the Conradson carbon value of the final product. However, the use of amixed solvent in the wax separation and acid treating steps is not as highly desirable as in the asphalt precipitation step; first, because the chilling necessary for precipitation of the wax can be accomplished satisfactorily with liquid propane alone and does not require liquid ethane; second, because of the added high pressure resulting from the presence of ethane which adds materially to the cost of the treating apparatus.

phaltic residue containing oil with a mixed light hydrocarbon solvent consisting of liquid ethane and propane, separating the undissolved asphaltic material from the solvent solution of oil and then removing a substantial portion of the ethane under pressure from the solvent solution of oil, 1 am able to conserve a large portion of the energy which would be required to liqueiy the ethane providing it were allowed to expand to substantially atmospheric pressure. Furthermore, the solvent solution of oil substantially free of ethane may be dewaxed adequately by utilizing the liquid propane for refrigeration by allowing to expand under reduced pressure and subse uently the dewaxed oil dissolved in liquid propane may be chemically treated under pressures substantially lower than would be -possible providing the ethane were not removed prior to such treatment.

It is, therefore, an object of my invention to comrm'ngle oil containing asphalt and w 2: under pressure in a mixture of liquid ethane and propane, separate the undissolved asphalt from the oil and wax dissolved in liquid ethane and propane, separate a substantial portion of the ethane present from the propane, oil and wax, chill the propane solution of wax and oil to a temperature sufificiently low to precipitate the wax by allowing a portion of the propane to vaporize under reduced pressure, separate the wax from the remaining oil and propane and then separate the propane from the oil.

It is another object of my invention to commingle oil containing asphalt and wax under pressure in a solvent composed mainly of liquid ethane and liquid propane, separate the undissolved asphalt from the oil, solvent and wax, separate a substantial portion of the ethane from the solvent, oil and wax, cool the solvent solution of oil and wax to a temperature sulficiently low to cause the precipitation of the wax by vaporizing a portion of the propane present under reduced pressure, separate the precipitated wax from the solvent and oil, chemically treat the oil dissolved in the solvent, separate the reaction products from the oil and solvent and subsequently separate the solvent from the oil.

The drawing is illustrative of one form of apparatus which I may employ to carry out my invention.

Oil containing asphalt and wax in tank 1 is withdrawn through valve 2 and line 3 into pump 4, which forces it through line 5 into agitator 6 where it is mixed with a light hydrocarbon solvent composed chiefly of ethane and propane coming from tank 8 through line 9, valve 10, line 11, pump 12 and line 13. The mixture in agitator 6 passes by means of line 7 into settling chamber 16 where the undissolved asphalt is permitted to settle out and is removed through valve 14: and line 15. The solvent solution of oil substantially free of asphalt passes from settling chamber 16 through line 17, pump 18, line 19, valve 20 and line 21 into chamber 22, where a. substantial portion of the ethane present is vaporized under pressure. This pressure will vary according to the ratio of ethane to propane in the solvent. The heat necessary for the ethane vaporization in chamber 22 is supplied by steam introduced through closed steam coil 23. The vaporized ethane in chamber 22 is removed through valve 24 and line 25 to compressor 26 which forces it through line 27 to condenser 28 where it is lique- 1 have diseovered'that by commingling an as fied and passes by means of line 29 to solvent storage tank 8.

The wax and oil dissolved in a solvent consisting substantially of liquid propane is withdrawn from chamber 22 through line 32 and passes into agitator 34 where it is mixed with filter aid, if desired, introduced through line 33. I may employ as filter aid or wax adherent material such substances as fullers earth, diatomaceous earth, kieselguhr, clay, sawdust or wood flour. The mixture of filter aid, wax, oil and solvent passes from agitator 3a through pressure reducing valve 65 into cooler 35 where sufficient liquid propane is allowed to vaporize under reduced pressure to lower the temperature sufficiently to precipitate the wax present. The vaporized propane is removed from cooler 35 through valve 36, and line 37 to compressor 38, which forces it through line 39 and line 27 to condenser 28 where it is liquefied and passes by means of line 29 to solvent storage tank 8.

The chilled propane solution of oil containing precipitated wax and filter aid in cooler 35 passes through valve 40 and line 41 to pump 42 which forces it through line 43 to filter press 44 where the wax and filter aid are separated from the solvent and oil.

The solvent solution of oil'free from wax and filter aid passes by means of line 46 to pump 47 which forces it through agitator 49 where it is mixed with sulphuric acid introduced through line 48. The acid treated oil dissolved in propane and acid reaction products pass from agitator 49 into settling chamber 50 where the acid reaction products are allowed to settle out and are removed through valve 66 and line 67.

The acid treated oil dissolved in liquid propane in settling chamber 50 is removed through line 51, valve 52 and line 53 into tower 54 where it is filtered through clay or sand to remove any remaining sludge present. The filtered oil dissolved in liquid propane passes from tower 54 into line 55 and thence to pump 56 which forces it through line 68 and valve 69 into heater 57 where the propane is vaporized by the aid of steam introduced through closed steam coil 58.

The vaporized propane passes from heater 57 by means of line 59 to compressor 60 which forces it through lines 61 and 27 to condenser 28 where it is liquefied and passes by means of line 29 to solvent storage tank 3.

The propane free oil in heater 57 is removed through valve 62 and line 63 to storage tank 64.

As an example of the method of carrying out my invention, one volume of oil containing wax and asphalt in tank 1 is thoroughly mixed in agitator 6 with three volumes of a mixed solvent consisting of about 20% to 50% ethane and the balance essentially liquid propane. This mixture is passed into settling chamber 16 where the undissolved asphalt is allowed to settle out and is removed through valve 14 and line 15. The waxy oil dissolved in the ethane-propane mixture then passes to chamber 22 where most of the ethane present is vaporized and removed through valve 36 and line 37 to pump 38 which forces it back to storage. During the ethane vaporization in chamber 22, sufficient heat is suputilized in settling chamber 16 for the separa-' is withdrawn from chamberl2'2 and mixed with filter aid, after which it passes "into cooler 35 where a sumcient quantity of liquid propane is vaporized to precipitate the wax. The chilled mass in cooler pases through filter press 44 where the wax and filter aid are separated from the oil and propane. The propane solution of oil is then treated with sulphuric acid, separated from the acid reaction products and then fractionated to separate the propane from the oil.

Where the raw charging stock contains oil and asphalt but no wax I first separate the asphalt from the oil by the use of the ethane-propane solvent containing 20% or more of ethane, remove most of the ethane present in the same manner as described in the foregoing example, chemically treat the oil dissolved in liquid propane and then separate the treated oil and propane.

The foregoing disclosure is merely illustrative of the process and isnot to be construed as limiting the invention, as many variations will appear to those skilled in the art.

I claim:

1. A process for the production of lubricating oil from oil containing asphalt which comprises commingling said oil under superatmospheric pressure in. a light liquid hydrocarbon solvent containing ethane and the remainder largely propane, separating the undissolved asphalt from the solvent and oiLseparating the ethane from the solvent and oil, acid treating the oil dissolved in the remaining solvent, separating the acid reaction products from said solvent and oil and subsequently separating said oil and said solvent.

2. A process for the production of lubricating oil from oil containing asphalt and wax which comprises mixing said oil with a light liquid hydrocarbon solvent of ethane and propane, separating the undissolved asphalt from the solvent, oil and wax, vaporizing most of the ethane present at about the same pressure as employed for the asphalt separation, chilling the oil and wax dissolved in remaining solvent to atemperature sufiiciently low to precipitate the wax by vaporizing a portion of the remaining solvent under reduced pressure, separating the precipitated wax from the oil and remaining solvent and subsequently separating said remaining solvent and oil.

3. A process for the production of lubricating oil from oil containing asphalt and wax which comprises commingling said oil under superatmospheric pressure ina light liquid hydrocarbon solvent of ethane and propane, separating the undissolved asphalt from the solvent, oil and wax, vaporizing and removing most of the 'ethane present in the solvent, oil and wax, chilling the oil and wax dissolved in liquid propane to a temperature sufliciently low to precipitate the wax by vaporizing a portion of the propane under reduced pressure, separating the precipitated wax from the oil and propane and subsequently separating the propane from the oil.

4. A process for the production of lubricating oil from oil containing asphalt and wax which comprises commingling said oil under. superatmospheric pressure in a light liquid hydrocarbon solvent comprising a mixture largely of ethane and propane, separating the undissolved asphalt from the solvent, oil and wax, separating most of the ethane from the oil, wax and propane, adding filter aid, cooling the oil, wax, filter aid and propane to a temperature sufficiently low to precipitate the wax by vaporizing a portion of the propane under reduced pressure, separatingthe wax and filter aid from the oil and propane and then separating the propane from the oil.

5. A process for the production of lubricating acid treating the propane solution of oil, separating the acid reaction products from the oil and propane and then separating the propane from the oil.

6. A process for the production of lubricating oil from oil containing asphalt and wax which comprises commingling said oil under superatmospheric pressure in a light liquid hydrocarbon solvent composed mainly of ethane and propane, separating the undissolved asphalt from the solvent, oil and wax, vaporizing and removing most of the ethane from the solvent, oil and wax, adding filter aid to the waxy oil dissolved in propane, vaporizing enough of the liquid propane under reduced pressure to chill the propane solution of waxy oil to a, temperature sufiiciently low to precipitate the wax, separating the wax and filter aid from the propane solution of oil, acid treating the propane solution of oil, separating the acid reaction products from the oil and propane and then separating the propane from the oil.

7. A process for the production of lubricating oil from oil containing asphalt and wax which comprises, commingling said oil under superatmospheric pressure in a light hydrocarbon solvent composed mainly of ethane and propane, separating the undissolved asphalt from the solvent and oil, separating a substantial portion of the ethane present from the solvent and oil, cooling the remaining solvent and oil to a temperature 8. A process for the production of lubricating 12G oil from oil containing asphalt and wax which comprises commingling said oil in a light liquefied hydrocarbon solvent comprising a. mixture of ethane and propane, separating undissolved asphalt from the solvent, oil and wax, vaporizing a portion of the solvent in one stage, reducing the pressure on the remaining mixture of solvent, oil and wax to vaporize another portion of the solvent in a second stage to efi'ect chilling of the oil and precipitation of wax, separating the precipitated wax from the remaining oil solvent solution and separating the remaining solvent from the oil.

9. A process for the production of oil from oil containing asphalt and wax which comprises comminglingsaid oil under superatmospheric pressure in a light'liquefied hydrocarbon solvent comprising a mixture largely of ethane and propane, separating undissolved aslubricatingv phalt from the solvent, oil and wax, separating a portion of the solvent under superatmospheric pressure in one stage, reducing the pressure on the remaining mixture of solvent, oil and wax oil from oil containing asphalt and wax which comprises commingling said oil in a light liquefled hydrocarbon solvent comprising a mixture largely of ethane and propane, separating undissolved asphalt from the solvent, oil and wax, vaporizing a large amount of the ethane in one stage under superatrnospheric pressure, reducing the pressure on the remaining mixture of solvent, oil and wax to vaporize the remaining ethane and a portion of the propane in a second stage to chill the oil and precipitate the wax, separating the precipitated wax from the remaining oil sol vent solution and separating the remaining solvent from the oil.

11. A process for the production of lubricating oil from oil containing wax which comprises commingling said oil in a light liquefied hydrocarbon solvent comprising a mixture largely of ethane and propane, vaporizing a part of the solvent in one stage and vaporizing another portion in the second stage to chill the oil and precipitate the wax, separating the precipitated wax from the remaining oil solvent solution and separating the remaining solvent from the oil.

12. A process for the production of lubricating oil from oil containing wax which comprises commingling said oil in a light liquefied hydrocarbon solvent comprising a mixture of largely ethane and propane under superatmospheric pressure, vaporizing a portion of the solvent in one stage under superatmospheric pressure, reducing the pressure and vaporizing another portion of the remaining solvent in a second stage to chill the oil and precipitate wax, separating the precipitated wax from the remaining oil solvent solu-.

tion and separating the remaining solvent from the oil.

13. A process for the production of lubricating oil from oil containing wax which comprises commingling said oil in a light liquefied hydrocarbon solvent comprising a mixture of largely ethane panacea stage to chill the oil and precipitate wax, sepainat= ing the precipitated wax from the remaining solution of propane and oil and separating the remaining propane from the oil.

i l. A process for the production oi lubricating oil from an oil containing asphalt which com prises cornmingling said oil with a liquefied nor= mally gaseous hydrocarbon solvent containing a major portion of propane and ethane to separate asphalt, separating the asphalt from the oil and solvent, removing a substantial portion of the ethane from the oil and solvent, treating the oil and remaining solvent with acid and separating the acid treated oil from the solvent.

15. A process for the production of lubricating oil from an oil containing asphalt which com= prises commingling said oil with a liquefied nor= mally gaseous hydrocarbon solvent containing a ma or portion of ethane and propane to separate asphalt, removing the asphalt from the oil dis= solved in said solvent, separating a substantial portion of the ethane from the oil dissolved in said solvent, treating the oil and remaining solvent with acid, treating the acid treated oil and remaining solvent with alkali and removing the remaining solvent from the oil.

16. A process as in claim 8 in which the li ue= fied hydrocarbon solvent comprising a mixture of ethane and propane contains approximately 20 to 50% of ethane.

17. A process as in claim 11 in which the light liquefied hydrocarbon solvent comprising a mix= ture largely of ethane and propane contains ap proximately ac to 50% of ethane.

ROBERT E. HAYLEIT.

Nil 

